Story Posted: 2011-01-01
Agriculture, Growing and Processing Canola
Source: CanolaInfo, Category:
Health & Nutrition
Q. What is Canola?
A. Canola's history goes back to the rapeseed
plant, but canola and rapeseed are not the same. Canola and rapeseed
have different chemical compositions, therefore the names cannot be
used interchangeably. In 1970's, Canadian plant breeders produced canola
through traditional plant breeding techniques. The major differences
are reduced levels of both glucosinolates (which contribute to the sharp
taste in mustard and rapeseed) and licosenic and erucic acids (two fatty
acids not essential for human growth) in Canola. "Canola"
then, refers worldwide to varieties with two percent or less erucic
acid in the oil and 30 micromoles per gram or less of the normally measured
glucosinolates in the meal. Canada's canola services major markets and
is internationally recognized as the industry forerunner in terms of
quality. In Canada, rapeseed is now only grown under special contract
and is used for industrial purposes.
Q. What does Canola look like?
A. Each canola plant grows anywhere from two
thirds of a meter (two feet) to two meters (six feet) tall and produces
groups of yellow flowers which in turn, produce seed pods about five
centimeters (2 inches) long. Each pod turns brown as it ripens and contains
twenty or more tiny round black or brownish-yellow seeds. Each seed
contains at least 40 percent oil and so canola is classed as an oilseed.
Canola is a cool-season crop and grows particularly
well on the prairies where cool night temperatures allow it to recover
from hot days and limited amounts of rainfall. Growing and harvesting
canola requires the same machinery used in growing cereal crops (wheat,
oats and barley). This allows farmers to switch to canola production
without a large cash expenditure.
Q. How is Canola produced?
A. There are two main types of canola grown,
the short growing season Polish type (Brassica rapa, a brown/yellow
seed) and the longer season Argentine type (Brassica napus, a black
seed). Fields are cultivated, seeded, fertilized, and herbicides/pesticides
may be applied to control insects, weeds and diseases.
Growing canola requires careful management on the
part of the farmer as the crop has to be closely monitored in order
to make sure it doesn't become diseased. Seedlings emerge four to ten
days after planting. From a taproot, bottom leaves form a rosette, which
send up a flower stalk as the plant grows. The flowering stage lasts
14 to 21 days and prairie fields at this time are a sea of brilliant
yellow flowers. The flowers of the Polish type canola are fertilized
by the wind and the Argentine type is self-fertilized. Bees, visiting
the flowers for nectar pollinate the flowers by carrying pollen. Once
the flowers are fertilized, pods for which take 35 to 45 days to fill.
The field is swathed when about one half of the seed pods have turned
color from green to yellow or brown. The swathed crop dries for approximately
ten days and is combined.
Q. What challenges does Canola present to the farmer?
A. Canola seed is very fine (about the size
of a radish or turnip seed) and it must be planted shallow in a moist
seed bed so the seed can germinate. Since canola is subject to attack
by several diseases and insects, canola is grown only one year in four
on the same field. Seed treatment is used to reduce seedling disease
and early flea beetle attacks. Herbicides are used to control weed growth.
All chemicals used are registered with the federal government and assessed
by the provincial government regarding application. The registration
process is rigorous, takes years of approval and involves Health and
Welfare Canada, Agriculture Canada, Environment Canada, Fisheries and
Oceans Canada as well as the chemical company. Plant breeders continue
to work to produce varieties, which have resistance to major diseases.
Q. Where does Canola go when it leaves the farm?
A. Approximately 45 percent of canola production
is trucked to the nearest processor where it is crushed for oil. Plants
are located across Manitoba, Saskatchewan and Alberta. Seed delivered
to a processing plant is graded according to a strict grading standard
established and maintained by the Canadian Grain Commission. Payment
to the farmer is based on grade; Canada No. 1 Canola to a sample grade.
Graded seed is then cleaned to remove plant stalks, grain seeds and
other materials. Processing canola involves heating and crushing the
seeds to release the oil. Once the oil is extracted, it is mixed and
processed according to end product requirements. Different treatments
are used to process salad oils, margarines and shortenings. The leftover
meal is processed into pellets or mash. The United States is our largest
importer of canola oil and meal. Approximately 40 percent of Canada's
canola seed is directly exported to Japan for processing by Japanese
crushers. Some canola seed is exported to Mexico and Europe. Canola
meal is exported to Indonesia, South Korea and Pacific Rim countries.
Q. Who uses Canola oil and Canola products?
A. Canola oil is recognized for its nutritional
qualities. It contains the lowest level of saturated fat of any fat
or oil on the market. It is high in both monounsaturated fat (which
may lower LDL cholesterol levels) and polyunsaturated fats, which are
essential in human diets. Canadians are the largest per capita consumers
of canola oil foodstuffs in the world. Canola is used in 80 percent
of the salad oil market, 56 percent of the shortening market and 42
percent of the margarine market. Besides being used in cooking oil and
sprays, salad dressings, margarines and shortenings, canola oil is also
used in deep frying, baking, sandwich spreads, coffee whiteners and
creamers. Consumer products containing canola carry the canola flower
logo. Canola oil is also utilized in inedible products such as cosmetics,
printing inks, suntan oils, oiled fabrics, plasticizers, plastic wraps,
pesticides and industrial lubricants. Research is underway to discover
other uses such as diesel fuel and industrial oils. Canola meal is used
as fertilizer and as high protein feed for livestock, poultry and pets.
Q. Seeds per pod?
A. Argentine: 25 to 35 seeds per pod, with
80 to 100 pods per plant. Polish: 15 to 25 seeds per pod, with 60 to
80 pods per plant. Low sulfur levels reduce the number of flowers resulting
in lower seed production.
Q. Can you remove wax stains with Canola Oil?
A. "Yankee's Home Hints." The directions
say merely to "rub the spots generously with vegetable or canola
oil and then gently wipe off any excess oil with a paper towel."
I read in one source that this may be a "fight grease with grease"
stain removal strategy. The chemical structure of wax is a long chain
hydrocarbon, therefore highly nonpolar. (as is canola oil) My best guess
is that wax is a nonpolar substance, and the simple chemistry adage
"like dissolves like" applies, so the nonpolar canola oil
dissolves the wax and removing the stain.
Q. How is Canola Oil Extracted?
A. The first stage in processing canola is
to roll or flake the seed. This ruptures cells and makes the oil easier
to extract. Next the flaked or rolled seeds are cooked and subjected
to a mild pressing process which removes some of the oil and compresses
the seeds into large chunks called "cake fragments". The oil
collected through this mechanical stage is marketed as expeller or first
press oil. The oil extracted during each step is combined. The oil is
then subjected to processing according to end product use. Different
treatments are used to process salad oils, margarine and shortenings.
Q. What is "solvent free" canola oil? What
are its advantages and disadvantages, including health and cost aspects?
A. "Solvent free" canola oil is also
known as Expeller, first press, or pure press oil. The solvent called
hexane is not used during the extraction process.
Q. What is cold pressed oil?
A. The difference between cold pressing and
hexane extraction of oilseeds lies in the initial extraction of the
oil from the seed. Cold pressing is a traditional method in which the
seeds are not heated before, during, or after the pressing process.
Seeds are selected, cleaned, and crushed; they are then mechanically
pressed at a slow pace to limit friction and avoid elevating temperatures
above 60°C. Its color, taste, and odor are much more pronounced
than those of refined oils.
Cold pressed oils, labeled as such and usually sold
in health-food stores are comparable to whole-wheat flour, which has
undergone very little processing and very little nutritive losses. Solvent-free
oil is not however, as expensive as cold pressed oil. There is a higher
antioxidant content to cold pressed oils (Vitamin E), which inhibits
the absorption of cholesterol, and a significantly lower content of
trans fatty acids. Despite these definite benefits, no regulation protects
the Canadian consumer against oils falsely labeled "cold pressed".
Overall, it is only a perceived difference that cold pressed oil is
a better, healthier product.
The price of cold pressed oil tends to be slightly
higher because of the lower recovery of oil.
Q. Is canola hot pressed or cold pressed?
A. First press, expeller press, and pure press
oils are all controlled between 38°C and 60°C. For regular processing,
the temperature range is 72-84°C.
Some Common Definitions
Cold Pressing: Cold pressed canola oil represents
a much smaller volume and is generally marketed in specialty food stores.
The production of cold pressed canola oil involves essentially the same
steps as described during mechanical extraction. In addition, the temperature
of cake during mechanical processing is controlled at 60°C or less
by water cooling the screw press. Oil recovery when using cold-pressing
techniques most often ranges from 75% to 85%. The price of cold pressed
canola oil tends to be slightly higher because of the lower recovery
of oil. Cold pressed canola oil is generally sold in bottled form directly
to consumers and is usually not used in further food processing.
Preconditioning: The first step in canola processing
where the seed is subjected to a mild heat and moisture treatment. This
treatment improves the subsequent oil extraction.
Crude Oil: Oil that is produced during the
extraction process. It contains various compounds that must be removed
to improve stability and shellfire.
Hydrogenation: is a special process used in
the production of margarine, shortening and other specialized products.
Large quantities of oil are heated in a vacuum; once the proper temperature
is reached, hydrogen is forced under pressure into the oil. The mixture
is whipped until the desired amount of hydrogen is incorporated into
the fatty acids. Hydrogenation is a process that changes the melting
behavior of liquid oils and improves stability. It permits the use of
higher cooking temperatures. This addition of hydrogen to the fatty
acid makes it a hydrogenated fatty acid.
When oils are hydrogenated, their unsaturated fatty
acids lose their natural form, called cis, and assume a new form called
trans. This chemical form called trans changes the entire behavior of
the unsaturated fatty acids. Instead of acting normally, they act much
like saturated fats: they increase the LDL (bad cholesterol) and decrease
the HDL (good cholesterol), and increase the risk of heart disease.
Canola Meal: is the solid portion of the canola
seed remaining after the oil is removed. It is used as a protein ingredient
in feed rations for poultry, swine, cattle, and fish.
Interesterification: is a process that makes
canola oil more solid. It involves mixing canola oil with other edible
oils that are more solid (saturated) by nature. (i.e. palm kernel oil)
The result is a semi-solid product without hydrogenation.
Winterization: the process that oil undergoes
in a plant setting to prevent it from going cloudy if stored in temperatures
under 5°C in a warehouse environment.
Deodorization: is the final step in the refining
of all vegetable oils, including canola. Deodorization involves the
use of steam distillation, which removes any residual compounds, which
could impart adverse odors and tastes. The oil produced is referred
to as "refined oil" and is ready to be packaged and sent to
Bleaching: is a process where the oil is moved
through natural, diatomaceous clay, which removes color compounds and
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